Diesel engine starter



May 19, 1942 .v R. A. COFFMAN DIESEL ENGINE STARTER -Filed July 15, 19554 sheets-sheet 1 wk MN 99 k& t 3% 33:5 ME gamma MR May 19, .1942.

R. A. COFFMAN 2,283,185 DIESEL ENGINE STARTER Filed July 15, 1955 4Sheets-Sheet 2 May 19, 1942. R. A. COFFMAN 2,233,185?

DIESEL ENGINE STARTER 1 Filed July 15, 1955 V 4 Sheets-Sheet 5 y 1942-R; A. COFFMAN DIESEL ENGINE STARTER za sass I Filed July 15, 1955 4Sheets-Sheet 4 MGR Patented May 19 1942 orrlca- DIESEL ENGINE STARTERRoscoe Alexander Coffman, Pittsburgh, 2a. Application July 15, 1935,Serial No. 31,519

zoolsims. (Cl. 121-37) invention relates to mechanism for gencratingrotary power and means for operating the same, and is of the samegeneral type as disclosed in my Patent No. 2,005,913, dated June 25,1935, covering a power generating system for use in the starting. ofinternal combustion engines, and wherein fuel cartridges or units areused for the purpose of generating propulsive.

gases for delivery to the starting motor to bring about the power orworking stroke of said starting motor. The principal object of theinvention is to provide means whereby the rectilinear movement of apiston is converted into a rotary movement by the interlocking relationof compound splined mechanisms to effect the rotary movement of heavybodies and particularly adapted for the starting of Diesel engines.

In the starting operation of Diesel engines great, difficulty has beenfound in securing a proper preliminary movement of the pistons to eflectthe starting of the engine due to the fact that a starting motor oftremendous force is required. Furthermore the compression within thecylinders of a Diesel engine is normally so high when the-valves of theengine are closed as to preclude rapid turning of the motor to effectstarting. It is therefore an object of this invention to provide astarting motor for Diesel engines which will be of sufiicient strengthto turn the engine at a relatively high rate of speed to efiect thestarting thereof, and which, at the same time, constitutes mechanismwhich is small and compact and which may be operated effectively with arelatively small motive force.

It is a purpose of this invention to provide a starting motor having,for example, a total pressure capacity of 563 cubic inches, capable ofdeveloping 229,770 convertible head pounds and capable of producingapproximately 260 horse power at the most convenient working speed.

In the starting of engines of the Diesel type it has been foundadvantageous to holdthe engine valves openduring the acceleratingmovement of the body mass, and to close such valves when the inertia ofthe mass has been overcome. To this end this invention provides meansoperable through the movement of the starting motor mechanism upon thesubstantial completion of the working stroke for instantaneously closingthe engine valves at' the proper moment.

Another object of the invention is to provide means within practicalmechanical limits for effecting the greatest-turning movement of thedriven member with a minimum movement of the dependent of and prior tothe 20 in this view the locking operating ease consistent with theemployment of a plurality of inner an members. a l

' A further objectof this invention is the provisionof clutch engagingelements adapted to effect a positive and complete engagement of clutchjaw teeth of the starting motor with the outer splined tubularcooperating teeth of the part to be moved, to-

gether with automatic means for resetting the motor clutch member forits nextpperation.

A .still further object of the invention is to provide means to utilizeinitial operating pressure to actuate the clutch engaging means invpower delivery movement of the motor shaft driving member to the part tobe moved.

These and other objects and advantages of this invention will becomeapparent in the following description, in which the appearance of likereference numerals indicate like parts, and in which:

Fig. 1 is a sectional view through the central longitudinal plane of thestarting motor, comprising an important part of the invention;

, Fig. 2 is a transverse sectional view taken on line 2-2 ofFig. 1;

Fig. 3 is an elevational end view of the clutching mechanism carried bythe starting motor shaft with parts in pre-engaging position, and

disc 4| is removed; 1

Fig. 4 is a longitudinal sectional view through a the starting motorclutch teeth shown in imperfect clutching relation to clutch teeth on'anengine shaft, said sectiontaken on the line 44 of Fig. 1, with thelocking disc 41 removed;

Fig. 5 is a view taken from the rear of Fig. 3 and also showing theparts in pre-engaging position,- said section taken on the line 5-5 ofFig. 1;

Fig. 6 is a longitudinal sectional view through the starting motorclutch clutching relation to clutch teeth on an engine shaft, said viewbeing similar to Fig. 4 except for the full clutching relation referredto;

Fig. 7 is an elevational endview of the clutching mechanism carried" bythe starting motor shaft with parts shown in power transmittingposition, this view being similar to Fig. 3 in that the locking disc 41isremoved; driving member, and at the sametime secure a Fig. is anelevational end view taken from teeth shown in full 3 ing a motor casingwhich may be joined into a unit by means of split draw rings I3 and I4which are channeled to fit over shoulders on abutting surfaces of thecasing sections and which are drawn tightly into locking engagement bymeans of suitable bolts in a well-known manner. The casing is adapted tobe placed in alignment with an engine shaft l5 having clutch teeth l6formed on its outer peripheral edge. Apertures l1 are formed in aperipheral-flange |8 formed on the front section In for convenientlyfixing the motor in operative position by means of bolts or othersuitable fasteners.

Within the motor casing which forms a cylinder is a piston l9 sealedagainst the cylindrical wall of the intermediate casing section II bymeans ofsuitable packing rings 20. Resting with its peripheral edgebetween the front and intermediate motor casing sections Ill and II andheld against rotation therebetween by means of dowel pins 2|, is a wormelement 22 which comprises a plate 23extendingtransversely across thefront endof the motor casing and a tubular element 24 which isconcentric with the longitudinal axis of the motor and which has formedon its interior, screw threads 25. An externally andinternally threadeddriving member 26 is rotatively associated with the piston IS. Thedriving member 26 is rotatively secured to the piston H! by means of alocking ring 21. A fiber gasket 28 1 lies between the abutting planesurfaces of the driving member 26 and the piston IQ for the purpose ofcushioning and absorbing the friction caused by relative rotationbetween the surfaces. Within the external driving member 26 and formedwith external threads adapted to engage with the internal threads on thedriving member 26, is an operating member 29. The operating member 29has internal threads which are adapted to engage external threads on aninternal driving member 30. The internal driving member 39 likewise hasinternal screw threads adapted to engage external threads on the crankshaft 35. The member 29 is mounted for free rotation against ballbearings 32 which are positioned between race rings 33 and 34 at thefront end of the motor.

The internal driving member 30 is operatively connected with the piston|9 by means of thelocking ring 35 which maintains the internal drivingmember 30 in rotative contact with the ball bearings 36 between the racerings 31 and 8B. To the end of the crank shaft 3| is connected, indriving relation, a clutch collar'39 which is provided with teeth 40 onits outer peripheral edge and which teeth are adapted to engage theclutch teeth l6 on the engine crank shaft l5. The specific constructionof the drivmg connection between the crank shaft 3| and the clutchcollar 39 will be more fully described hereinafter.

The piston I9 is normally retained at the rear of the cylinder by meansof a relatively heavy coil spring 4| which rests against the internalsurface of the piston l9 at one end, and against the plate 23 of theworm element 22 at its other end. When the piston I9 is moved forwardunder a power impulse against the tension of the coil spring 4|, thedriving member 26 and the internal driving member 36 are moved forwardsimultaneously and to the same degree. Since the worm element 22 isfixed against rotation and since the driving member 26 and the internalon the crank shaft 3| are in engagement with the internal threads on theinternal driving member 30, the crank shaft 3| will be rotatedanticlockwise when considering for instance Figs. 1,

3 and 7 of the drawings.

The pitch of the threads on the various relatively movable threadedmembers and the number of these members will determine the number ofrevolutions imparted to the crank shaft 3| for each operating stroke ofthe piston l9. In the present instant the threads on the variousthreaded members are so related that in its forwardmovement the drivingmember 26 is given one-half revolution while the operating member 29 isgiven one complete revolution. The internal drive member 33 will receiveone and onehalf revolutions, while .two complete revolutions will beimparted to the crank shaft 3|. The number of turns imparted to thecrank shaft 3|, or any of the other threaded parts, may be varied inaccordance with the pitch of the threads on their respective surfaces.

It is to be understood that the number of inter-threaded driving membersmay be multiplied to gain greater power and a higher number of perstroke revolutions of the crank shaft.

The crank shaft 3|, Figs. 3 to 8 inclusive, has formed at its front enda plurality of longitudinal splines 42 which are adapted to registerwith spline ways 43 formed in the clutch collar 39. The spline ways 43are substantially twice as wide as the splines for the purpose ofproviding a lost motion connection between the clutch collar 39 and thecrank shaft 3|. The clutch collar 39 is normally urged in acounter-clockwise direction (as shown in Fig. -5) with respect tothe-crank shaft 3| by means of spring members 44 which are bent aroundpins 45 extending from the rear surface of the clutch collar 39. One endof the springs 44 bears against the splines 42 of the crank shaft 3|,while the other end of the springs 44 are held under tension by contactwith a shoulder on the periphery of theclutch collar 39. Thisarrangement is provided to insure the proper engagement between theengine shaft clutch teeth I6 and motor shaft clutch teeth 40. Should theclutching collar 39 be aflixed to the crank shaft 3| rigidly withoutprovision vfor engaging the teeth before the application of power, it ispossible that the teeth might engage imperfectly as shown in Fig. 4.Under such conditions and under the influence of the tremendous powergenerated by the starter motor, the teeth It consequently follows thatsince the external threads clutch teeth It and 40, perfectly. as shownin Fig. 6 of the drawings. Should an imperfect engagement between theseteeth initially be eflected, as shown in Fig; 4 (creating momentarily aslight binding eilect'between said teeth) continued rotary andlongitudinal movement of the crank shaft 3| will be permittedirrespective of the clutch collar 39. and this due to the'lost motionconnection between the clutch collar 39 and the crank shaft 3|, thusplacing thespring members it under tension and. permitting the floatingclutch collar 89 to adapt or adjust itself to the proximate" end ofitspower stroke. The operat- H which is reached by the'piston I 9 at theapjing rod it may contact withsome mechanism generally indicated atllfwhich isadapted'to close the valves on the-Diesel engine when thepiston IQ of the starting motor has moved the rod 63 'into operatingcontact with the mechafecting the operation of the engine valves may be10' member to be turned (engine shaft clutch teeth).

In other words, clutch collar 39 is not only moved forward in alongitudinal or axial direction due to its connection with the crankshaft 3|, but is ni'sm 6!. Suitable intervening mechanism for efreadilyprovided by those skilled in the art.

Communicating with the exhaust outlet 51 is an exhaust chamber 85 whichcommunicates with'the interior -of the motor cylinder. This chamber isnormally closed by meansof a valve capable ofvhaving a slight rotativemovement in dependently of .the rotative movement of the crank shaft,and this rotative or adjusting movement is effective before the splines42 come into direct driving engagement with the clutch collar 39, thusserving to center accurately and engage the clutch teeth as shown inFig. 6-to insure a firm and positive turning action of the shaft I 5without any danger of injury to the teeth on either shaft.

The-clutch collar 39 is heldbetween an abutting shohlder'to on the crankshafttl and a locking disc 41, which is screwed into the crank shaft 3|by means of screw threads 48, formed on $6 on the end of a valveoperating rod 61' which extends through the piston lS-and which liesconcentrically within the sleeve 59. Famed on the inner end of the rod61 is a head 68 between which and the end of the sleeve 58 lies acoilspring 69 which is adapted to maintain the valve head 86 against itsseat. Within the sleeve 59 and surrounding the -rod 6'! is a hammersleeve 10. Within the hammer sleeve 10 and about the rod 61 is a secondcoil spring I! which is adapted to effect the opening of the exhaustvalve by moving the head 66 from its seat. The opening of theexhaustvalve is effected when the piston its external rearwardlyextending boss 48a. Be-

tween the locking disc 41 and the clutch collar 39 is a washer 49 whichis adapted to seal the clutch collar 39 against leakage oflnbricationthrough the spline ways formed therein. The

is an inlet aperture 56 and an exhaust'aperture 51. Formed in the headof the motor is a third aperture 58 through which compressed air may beadmitted for a purpose hereinafter more particularly described. Theinlet Slmay be connected with any one of the sources of fluid pres:

sure which will be hereinafter described. As suming that fluid pressureis admitted to the inlet 56, the piston is will be driven forwardagainst the tension ofthe coil spring 41 and the threaded members 2s,as, so; and 3| will be rotated as described. Attached to the piston l9by means of screw threads is a sleeve 59 which has formed thereon at itsforward end a tapered head 60 which engages the in-bent fingers of aspring sleeve 6!, which is attached inside of the hollow crank shaft 3|by mean of rivets 62. When the piston I9 moves the sleeve 59 forward.

its engagement with the'spring sleeve 6| serves to move the crank shaft3| forward so that the teeth 40 on the clutch collar 39 come intoengagement with the teeth It on the engine shaft -l5. Thus a rotation ofthe engine shaft I5 is effected.

Since this starting motor is particularly adapted for use with Dieselengines, and since the exhaust valves on Diesel engines are usually heldin open positionuntil sufficient monientum' from the exterior of themotor casing to a point within the cylinder of the intermediate sectionI9 moves forward in the cylinder and when the same has reached the endof its power stroke. During the forward movement of the piston the coilspring II is compressed ,-between the.inner surfaceof the piston and'thehead 68 on the stem .81. This pressure is, however, insufficient torelease the valve head from its seat and the positive movement of thevalve is not effected until the hammer sleeve 10 contacts the head 68 onthe rod Cl. After the rod 61 has been moved positively in this manner todisengage the notch 12a .on the rear end of the valve stem from the.

spring member 12, theaccumulated power of the tensioned coil spring] Iwill serve to move the valve head 68 away from its seat with asnapaction to ensure a, complete opening; In its open position the valveis held positivelyby engagement of the spring fingers 12 within the sec-7 ond notch 12b on the rear of the valve-stem.

The valve closes when the piston I9 is returned to its position of restby the spring II and when the coil spring 68 is compressed between thevalve stem head 88 and the front end of the casing 59. I

Communicatingdirectly with the interior of the cylinder andthe exhaustport 51 is a passage which is-separated from the exhaust port 5! bymeans ofa frangible disc ll. The disc 14 may be removed and replaced byremoving the plug I5 and the same is held in position bythe plug I5which passes through the exhaust chamber 65, but about andyth'roughwhich gases may flow freely from the chamber 65, into the exhaust 51'during the normal exhausting operation. Should for any reason adangerous condition of pressure be created within the cylinder, thefrangible disc or diaphragm I4 is adapted to rupture before seriousdamage can 'be done by such abnormal condition.

The inlet 58 may be connected to a source of air pressure. The inlet iscontrolled by a ball valve 1'! which is spring pressed to its seat bymeans of a spring 18. pounds is commonly ound where Diesel engines areused. and this pressure, when applied to the starting motor, serves asacushioning pressure for permitting effective and easy coupling up of theengine and smooth connection between the starter and the Air pressure ofto starter shafts and maintaining a engine by occupying the open spacesin the breech mechanism, in the burning chamber, and in the spacebetween the piston l9 and the cylinder head I2. By the use of airpressure the clutch teeth may be inter-engaged by an initial forwardmovement of the piston I9 prior to the initiation of its full powerstroke. Such air sup-v permitting the clutch teeth to be formedintegrally with the end of the crank shaft 3I or for permitting a clutchcollar to be fixed to the crank shaft, the modified clutch engagingmechanism illustrated in Fig. 9 has been provided. This mechanismpermits the use of a rigid clutching device on the end of the crankshaft and still insures proper connection between the clutch teethbecause of the fact that the clutch teeth carried by the endof the crankshaft N are moved into engagement with the clutch teeth on the engineshaft prior to the application of operating pressure to the piston I9.This mechanism will now be described.

- A housing I54 has been provided with screw threads adapted to engagethreads on a relatively large bore in the back of the motor head I2. Agasket I55 may be provided between a shoulderon the housing I54 and thebody of the motor head" for the purpose of sealing the joint againstpressure leakage. In the housing is pro 'vided an aperture, I56 intowhich may be threaded any one of the breech and combustion mechanisms'hereinabove described. In lieu of the attachment which may be made at I56 the pressure generating mechanism may be attached at I51 in the motorhea'd I2 and the inlet I56 may be sealed with a plug. In the event thepressure mechanism is attached at I51, which communicates directly withthe interior of the cylinder, the inlet I58 isbrou'ght in communicationwith a source of air pressure for effecting the initial operation of ,apiston I59 within the housing I54.' Thepiston I59 is faced on its rearwith a layer of asbestos insulating material I60 which is covered with athin spinning plate I6I for the purpose of protecting the piston I59against excessive heat which might have a detrimental effect on'theelasticity of the springs associated with the piston I59. Surroundingthe piston I59 and threaded into the front end of the housing I54 is ashell I62 between which and the piston I59 is a coil spring I63 whichnormally serves to retain the piston I59 in its position at the rear ofthe housing I54. The front end of the piston I59 is adapted to slide ina reduced bearing surface formed on the front end of the shell I62.Around the'frontend of the shell I62 and in that portion which forms aright angle to its main body are a plurality of passages I64 for apurpose which will hereinafter become evident. The piston I59 isinwardly beveled along its front edge at.l65, which beveled surface liesin contact with pins I66 which are slidably mounted in a sleeve I61,which at its forward end is screw threaded into the piston I9, and whichcom. presses a gasket I68 between a shoulder formed thereon and thepiston I9 for sealing the two in spee s:

gas tight relation. Splined to the sleeve I61 and lying concentricallytherein is a second sleeve I69 which is adapted to move longitudinallyrelative to the sleeve I61, but which is normally locked thereto, by'means of locking pins I10 which pass therethrough and into aperturesin' the sleeve I61, which apertures lie directly over the pins I66carried by the sleeve I61. The looking pins I10 are normally pressed andretained in locking position by spring fingers "I which are fixed to thesleeve I69 by rivets I12. -From the description as thus far given it isevident that when the piston I59 moves forward relative to the sleeve I61, and its forward beveled surface I65 contacts the pins I66, thesepins are pressed inwardly, consequently the locking pins I10 are pressedinwardly against the tension of the spring fingers III. As soon as thelocking pins I10 have been pressed inwardly sufiiciently far to lieoutside the plane of the sleeve I61, the internal sleeve I69 will befree to move forward lloengitudinally with respect to the externalsleeve The external sleeve I61 is formed, at its forward end with anenlarged bore and the internal sleeve I69 is formed with a shoulder I13which is adapted to lie in contact with the flange formed between theenlarged bore and the smaller bore of the sleeve I61. u Between theshoulder I13 and a sleeve member I14, carried at the forward end of thesleeve I61, is a coil spring I15. Within the coil spring I15 is a secondcoil spring I16 which contacts the front end of the internal sleeve I69and the element I11 to which the crank shaft operating tube 59 isattached.

Within the piston I59 is a central bore through which the extension 61'of the valve 61 passes. This bore is closed bya screw threaded plug I18which supports one end of a coil spring I19, which is of greaterstrength than the combined strength of coil springsl15 and I16. Theextension 61 of the valve stem 61 likewise passes through a plug I whichsupports the opposite end of the coil spring I19 and which is'slidablymounted withinthe central bore of the piston I59 and with relation towhich the valve stem 61 may slide. The valve stem is screw threaded tothe valve stem extension 61', and the extension is threaded to theinternal sleeve I69 by means of threads at I8I on the extension of thevalve stem. It is therefore evident that the piston I59 may movelongitudinally with respect to the valve stem 61 and its attendantmechanism,

and that the internal sleeve I69,;which is attached to the valve stemextension 61', may move longitudinally witnrespect to the externalsleeve I61 when the locking pins I10 are released. Furthermore it willbe noted that the valve stem 61 will move longitudinally with respect tothe easing 59 and that the casing 59 may move longitudinally withrespect to the piston I9.

When air pressure is admitted through the inlet I58 the piston I59 movesforward against the tension of thespring I63. During this movement thebeveled surface I65 on the end of the piston I59 moves the pins I66inwardly against the locking pins I10 to move the locking pins I10 outof the plane of the external sleeve I61. When during the movement of thepiston I59 the plug I80 carried thereby comes in contact with the end ofthe internal sleeve I69, the internal sleeve is moved forward withrespect to the ex-- I61 against the tension of the which carries thetube 59 is moved forward so that its head (see Fig. 1) is brought tobear against the fingers of the spring sleeve 6| which 'is riveted tothecrank shaft 3|. This serves to move the crank shaft forward to engagethe teeth thereon with the teeth on the engine shaft. If this engagementis effected before the termina-. tion of the forward movement of thepiston I59,

the head on-the tube 59 slips r iastthe Sprin fingers into the enlargedportion of the spring sleeve' 6| to avoid further forward pressure shaft3| begins to rotate under the initial impulse from the piston I9, andthen the added forward pressure will serve center the teeth ac-'curately. I I

The sliding joint between the members I 14 and I-lIis packed by meansofa leather gasket I82, and the valve stem 61 is surroundedby a leathergasket I83 which serve to seal; the joint against pressure leakage. v j4 The forward movement of. the piston I59 under the impulse of 'airpressure is limited by the opening I86 between the internal body portionof the casing I54 and the rear'end oi the shell I62. When the piston I59moves beyond this opening the air pressure will flow past the piston andthrough the openings I64 into contact with the rear face of the pistonI9, thus moving the piston forward to a slight'jdegree, rotating thecrank shaft 3| to insure proper connection between the clutch teethbefore heavy pressure is admitted from the. pressure generating'deviceconnected at I51.

.allow the interengaging teeth of the clutch means to come into properand intermeshing relation,

rotary crank shaft operated thereby. a clutch .-member associatedwithsaid' crank shaft adapted and that thereafter a much higher workingpressure fluid is admitted to the starter cylinder for creating the mainor normal power stroke of the starter piston for the actual cranking orstarting operation, and in this connection, it is to be I noted that inFig. 1 theair pressure is admitted "at 58', and in Fig. 9 at I58. I

' 'What Iclaim is': 1 t

. 1. In an engine starter having a piston and a to engage a member to beturned, and'means shaft and prior to the application of normal Theexhaust valve I66' in this form of the in- I vention is similar to thatand operates like that shown in Fig. 1 of the drawings, and theoperation thereof need not be repeated. It will suffice to say. thatduring the exhaust movement of their normal position.

' -As hereinbefore indicated, it is possible to thepressure on thepiston I59 is relieved the '5 several springs return their associatedparts to 50,

acting on said clutch member and permitting the same to move intocomplete: engagement with the member to-be turned independently of thecranking or power'r'otative movement of the crank working power tosaidclutch member.

2. ma starting motor, a piston adapted to be moved by fluid pressure, arotary crank shaft associated with said-piston and adapted to be movedby said piston, clutch teethcarried by said shaft adaptedto move intodriving-relation with teeth on a part to be moved and capable of slightsaid clutch teeth into driving relation, means thereafter operative todrive said piston through a working stroke, and "mechanism operative on"said clutch teeth to move the same to inoperative or non-drivingposition with respect to said crank .shaft after the working stroke ofsaid piston.

3.'In a'starting motor, a piston adapted to be moved "by fluid pressure,a rotary crank shaft .associated with said piston andadapted to bemovetf'lbngitudinally by said piston into driving relation for startingpurposes, clutch teeth car-'- ried by'said shaft adapted to move intodriving relationwith teeth on a part to be moved, a lost motionconnection between said shaft and said clutch teeth permitting limitedrelative rotation therebetween, means normally urgingsaid clutch teethin the same direction as the direction of rotation'of said crank shaft,means for initially projecting said clutch teeth into driving relation,

and means thereafter operative to move saidpiston through a workingstroke.

connect a pressure generating chamber with the inlet, I56, in whichevent the inlet I51 may be closed by means of a plug.- When the pressuregenerating mechanism is connected with the inlet I56, the initialgeneration of the pressure serves to operate the clutch teeth engagingmechanism as hereinbefore described, and the continued generation of thepressure will maintain this disclosure maybe modified and combined in.

various ways not specifically hereinabove set forth-and it is the objectof the invention, therefore, not to limit itsjpracticeto any specificform,

'but since various modifications may be madeit is specificallyunderstood that the practice of the invention shall. be in no waylimitedexcept as limitations may be imposed thereonby the scope 'of thesub-joined claims.

It is-to be definitely understood that in both 4. In a starting motor, apiston adapted to be moved, by fluid pressure, a rotary crank shaftassociated with said piston and adapted 'to be moved by said piston,clutch teeth carried by said shaft adapted to move into driving relationwith teeth on a part to be moved, a lost motion connection between saidshaft and said clutch teethpermitting limited relative rotationtherebetween, means for maintaining said clutch teeth at one limit' oftheir relative rotative movement and urged in a direction similar to thedirection of rotation of the crank shaft when said teeth are not indriving relation, means for initially pro- .Jecting said clutch teethinto driving relation, and means thereafter operative to move saidpiston through a working stroke.

5. In a starting motor, a piston adapted be movedby' fluid pressure, arotary crank shaft associated with said piston and adapted tobe moved bysaid piston, clutch teeth carried by. said shaftadapted to move intodriving relation with teeth on a. part to be moved, a lost motionconnection between said shaft and said clutch teeth permittinglimitedrelative rotation therebetween.

forms of applicantsinvention air pressure of .approximateLv to lbs.maybe used to rotative movement and urged in a direction similar to thedirection of rotation of the crank shaft when said teeth are not indriving relation,

means for initially projecting said clutch teeth into driving relation,and means thereafter operative to move said piston through a workingstroke.

6. In a starting motor, a piston adapted to be moved by fluid pressure,a rotary crank shaft associated with said-piston and adapted to bemovedby said piston, clutch teeth carried by said shaft adapted to moveinto driving relation with teeth on a part to be moved, a lost motionconnection between said shaft and said clutch teeth permitting limitedrelative rotation therebetween, means for admitting auxiliary fluidpressure to said motor to move said piston and project said clutch teethinto driving relation, and means for thereafter admitting a differentcharge of fluid pressure to said motor'to move said piston through aworking stroke.

'7. In a starting motor, a piston adapted to be movedby fluid pressure,a rotary crank shaft associated with said piston and adapted to be movedby said piston, clutch teeth carried by, said shaft adapted to move intodriving relation with teeth on a part to be moved, a lost motionconnection between said shaft and said clutch teeth permitting limitedrelative rotation therebetween, resilient members interconnectingsaidassams 10. In a starting motor, a piston, a rotary crank shaftassociated with said piston and adapted to be moved by said piston, aclutch member carried by said shaft adapted to be moved into drivingrelation with a part to be driven, clutch operating means carried bysaid piston, a sec- 0nd piston operative on said clutch operating meansto move said clutch into driving rela 'tion, means for admitting fluidpressure to each of said pistons, and means limiting the movement ofsaid second piston.

11. In a starting-motor, a piston, a rotary crank shaft associated withsaid piston and adapted to be rotated by said piston, a clutch membercarried by said :shaft adapted to be moved into driving relation with apart to be driven, clutch operating means carried by said piston, asecond piston operative on said clutch operating means to move saidclutch into driving relation, means for admitting fluid pressure to saidlast named piston to project said clutch member, and independent meansfor admitting fluid pressure to said flrst named piston to move the samethrough a working stroke.

12. In a starting motor, a piston, arotary crank shaft associated withsaid piston and adapted to be rotated by said piston, a clutch membercarried by said shaft adapted to be moved into driving relation with apart'to be driven, clutch operating means carried by said piston, anauxiliary cylinder in said motor, a second piston within said cylinderoperative on said clutch I operating means to move said clutch intodrivshaft and said clutch teeth for maintaining said teeth at one limitof their relative movement and urged in a direction similar to thedirection of rotation of .the crank shaft when said teeth are not indriving relation, fluid pressure means for initially projecting saidclutch teeth into driving relation, and further fluid pressure meansthereafter operative to move said piston through a working stroke. 1

8. In a starting motor, a piston adapted to be ing relation, means foradmitting fluid pressure to said last named piston to project saidclutch member into driving relation, vents in said cylinder to limit themovement of said second named piston, and independent means for admittinmoved by fluid pressure, a rotary crank shaft associated with saidpiston and adapted to be moved by said piston, clutch teeth carried bysaid shaft adapted to move into driving relation with teeth on a part tobe moved, a lost motion connection between said shaft and said clutchteeth permitting limited relativerotation therebetween, spring mechanismnormally tending to move said teeth in a direction similar to thedirection of rotation of said crank shaft,

members interconnecting said shaft and said :clutch teeth at one limitof their relative rotative' movement when said teeth are in drivingrelation with respect to said shaft, auxiliary fluid pressure means forinitially projecting said clutch teeth into driving relation, andfurther fluid pressure means thereafter operative to move said pistonthrough a working stroke, said spring mechanism acting on said clutchteeth to move them to an inoperative position at the other limit oftheir relative rotative movement after a working stroke of said piston.

9. In a starting motor, a piston, a rotary crank shaft associated withsaid piston and adapted to be moved by said piston, a clutch membercarried by said shaft adapted to be moved into driving relation with apart to be driven, clutch operating means carried by said piston, asecond piston operative on said clutch operating means to move saidclutch into driving relation, and means for admitting fluid pressure toeach of said pistons.

" fluid pressure to said first named piston to move thesame through aworking stroke.

13. In a starting motor, a piston, arotary crank shaft associated withsaid piston and adapted to be rotated by said piston, a clutch member.carried by said shaft adapted-to be moved into driving relation with apart to be driven, clutch operating means carried by said piston, anauxiliary cylinder in said motor, a second piston within said cylinderoperative on said clutch operating means to move said clutch intodriving relation, means for admitting fluid pressure to said last namedpiston to project said clutch ,member into driving relation, vents insaid cylinder to limit the movement of said second named piston, and apassage-between said vents and said flrst named piston whereby saidsecond named piston is flr'st movedjandthereafter pressure is app ied tosaid-flrstnamed piston to drive ,the same through a wo -king stroke.

starting motor, acylinder, apiston ectilinear movement in said cyl- ,a'-sh'a.ft located along the longiaxis of-said cylinder, meansinterconnectin'ggsaid. piston and said shaft whereby -moveinentof-saidpiston effects rotation of saidshaftjffafclutchmember carried at one endof said shaft adapted to be moved into driving relation with a part tobedriven, clutch operating means "extending longitudinally through saidshaft-,fa second piston-operative on said clutch operatingfmeans to movesaid clutch into drivingi'relation, means for admitting fluid pressureto each orsaid pistons to effect their movement.

15;11'1 a starting motor, a cylinder, 9. piston mounted for rectilinearmovement in said cylinder acrank shaft located along the longitudinalaxis of said cylinder, means interconnecting said piston and said shaftwhereby movement of said piston efiects rotation of said shaft, a clutchmember carried at one end of said shaft adapted to be moved into drivingrelation with a part to be driven, clutch projecting means extendinglongitudinally through said shaft and piston, a second cylinder axially.associated with said first named cylinder, 9. second piston within saidsecond cylinder operative on' said clutch operating means to move saidclutch member into driving relation, means for admitting fluid pressureto said second piston to project said clutch member, and independentmeans for admitting -iiuid pressure to said first named piston to movethe same through a working stroke.

16. In a starting motor, a cylinder,-a piston mounted for rectilinearmovement in said cylinder, a crank shaft located along the longitudinalaxis of said cylinder, means intercom ting fluid pressure to said secondpiston to project said clutch member, vents in said second cylinder tolimit the movement of the piston therein, and independent means foradmitting fluid pressure to said first named piston to move the samethrough a working stroke.

17. In a starting motor, a cylinder, 2. piston mounted for rectilinearmovement in said cylinder, a crank shaft located along the longitudinalaxis of said cylinder, means interconnecting said piston and said shaftwhereby movement of said piston eiiects rotation of said shaft, a clutchmember carried at one end oi said shaft adapted to be moved into drivingrelation with a part to be driven, clutch projecting means extendinglongitudinally through said shaft and piston, a second cylinder axiallyasso ting fluid pressure to said second piston to proiect said clutchmember, vents in said second cylinder to limit the movement of thepiston therein, and a passage between said vents and said. first named.piston whereby said second named piston is first moved and thereafterpressure is applied to said first named piston to drive the same througha working stroke.

18. In an engine starter having a piston and a rotary crank shaftoperated thereby,-a clutchv member associated with said crank shaftadapted to engage a member to be turned, and means permitting saidclutch member to adjust itself to the crankshaft and the member to beturned and according to varying conditions for insuring completeengagement of the clutch member with the member to be turned and priorto the application of normal working power to said clutch memberysaidmeans normally tending to urge said clutch member being normally urgedin a ciated with said first named cylinder, a second the clutch memberin the same direction as the direction of rotation of said crank shaft,

19. In an engine starter having a piston and a rotary crank shaftoperated thereby, a clutch member associated with said crank shaftadapted to engage a member to be turned, and means permitting saidclutch member to initially move in a rotative direction independently ofthe rotative movement of the crank shaft and adjust itself to the memberto be turned andaccordin to varying conditions for insuring completeengagement of the clutch member with the member to be turned and priorto the application of normal working power to said clutch member,

direction similar to the direction of said crank shaft. I

20. In an engine starter having a longitudinally moving telescopingpiston and a rotary crank shaft operated thereby, a clutch memberinitially movable in the same longitudinal direction as said pistonassociated with said crank shaft and adapted to engage a member to beturned, and

of rotation means acting on said clutch member through longitudinalsplines to insure said initial movement and complete driving engagementof said clutch member with the member to be turned prior to theapplicationof normal working power to said clutch member, said meanstending normally to urge the clutch member in a direction similar to thedirection of rotation of the crank shaft. 1

ROSCOE ALEXANDER CO

